The method and apparatus of this invention lie in the field of producing concrete structures with a plurality of uniform recesses. The invention is more particularly directed to producing mausoleum structures with several tiers of horizontally spaced crypts with minimum costs for labor and equipment.
Forms for pouring concrete foundations, walls, and the like have been made for many years with various types of lumber, including plywood. They are built up by carpenters using multitudes of nails and then must be torn apart for re-use. Since the concrete products are rather rough, the lumber can be used quite a few times in spite of the cumulative damage. Even so, the cost of the material is high and the labor is very expensive.
In cases where particular shapes are to be repeated many times it is possible to build up forms in a small number of composite sections which need not be completely torn down after each use. There is considerable saving in labor and in wear and tear on the lumber but the total cost is still high.
When hollow walls of various types are to be constructed it is necessary to use internal forms, or cores. Such cores are difficult to remove because they adhere to the recently set concrete and usually must be broken down to a great extent. Many kinds of collapsible cores have been proposed, using collapsible or separable walls or corners. While they are generally satisfactory in use they ordinarily have a multitude of relative movable parts requiring rather accurate fitting and complicated connecting means, rendering their first cost rather high and requiring a great deal of maintenance.
A great many mausoleums are being built at the present time. The basic portion of such a building is a monolithic concrete structure having a flat vertical front face pierced by a plurality of tiers of deep elongate crypts or recesses extending horizontally into the structure and arranged in side by side spaced relation with thin partition walls between them. The normal construction process includes preparing a base slab, mounting a plurality of core forms on the slab in spaced relation, pouring concrete to form the partition walls and produce a new slab, and removing the cores or forms, the process being repeated to complete the desired number of tiers.
The majority of such structures have been built using conventional built up wooden forms, some of them including prefabricated metal corner pieces. These forms are wedged so tightly in the hardened concrete recesses that they must completely broken down to remove them. Various collapsible forms have been proposed for use in this particular type of construction but they all suffer from various drawbacks. Some of them employ only a few components and are made of fiberglass and a suitable plastic binder. While they are simple they are generally inadequate becuase the walls of the form are not rigid enough to withstand the loading of the concrete and produce distorted recesses which make removal of the forms difficult. They also have inadequate protection against leakage of flowable concrete into the recess, requiring subsequent chipping operations to obtain a satisfactory finished recess. Other types employ a large number of separable parts which require high accuracy in manufacture and are difficult to assemble so that all of the parts fit together properly. Moreover they must be dismantled into many components in order to remove them from the recesses.